ALL MANUFACTURERS OF SMALL OFF-ROAD ENGINES and EQUIPMENT
ALL RECREATIONAL ENGINE/VEHICLE MANUFACTURERS
ALL MARINE AND PWC ENGINE MANUFACTURERS
ALL COMPRESSION IGNITION OFF-ROAD MANUFACTURERS
ALL SPARK IGNITION OFF-ROAD MANUFACTURERS
ALL AFTERMARKET PART MANUFACTURERS
ALL RETROFIT KIT MANUFACTURERS
ALL OTHER INTERESTED PARTIES

The California Air Resources Board (ARB) staff is developing certification procedures for aftermarket parts and
conversion systems for off-road categories. These categories include lawn and garden equipment, marine vessels,
recreational vehicles, and farm and construction equipment. A Board hearing to consider adoption of these procedures
is tentatively scheduled on October 22, 1998.

The use of ineffective aftermarket parts in mobile sources has been shown to compromise the integrity and/or
durability of the original certified emission control systems. Consequently, ARB requires on-road aftermarket parts
manufacturers to demonstrate, through vehicle testing, that an aftermarket part will not increase vehicle emissions
before that part can be sold or installed. Similar requirements have been developed for aftermarket alternative
fuel retrofit systems (systems designed to allow a motor vehicle to operate on alternative fuel).

The current off-road regulations do not allow the use of add-on parts, modified parts, or fuel conversion systems
on regulated off-road sources. The ARB is proposing certification procedures for off-road aftermarket parts that
will allow manufacturers to demonstrate that their parts do not increase emissions. These certification procedures
will therefore allow aftermarket parts manufacturers to participate in a market that is not currently available
to them, while also helping to insure the integrity of the ARB's entire off-road regulatory program.

As a result, staff believes that the proposed regulations will provide appropriate guidelines for the manufacturer
to follow and encourage standardization in this industry which will benefit the manufacturer and the purchaser
of the vehicle/engine/equipment.

Attached is a preliminary report describing the staff's proposal. In general, the staff is proposing certification
procedures that are directly analogous to those that have been in place for on-road aftermarket parts. Proposed
testing procedures are identical to those used for certification of the applicable off-road vehicle, engine, or
equipment category. Detailed regulations and test procedures that are being proposed are available on the Internet
at www.arb.ca.gov.

The staff encourages industry and other interested parties to contact staff with any comments or questions and
to provide written comments by August 21, 1998. Staff has provided a Comment Form for convenience. All documents
may also be available by contacting Subhadra (Su) V. Nathan, Air Pollution Specialist, (626) 575-6671, or snathan@arb.ca.gov,
or Air Resources Board, Mobile Source Control Division, 9528 Telstar Avenue, El Monte, CA, 91731.